Water is a precious resource and one of the natural elements that needs to be conserved. Many regions in the world have scare water resources and the heavy industrial use further depletes the natural resource in developed and developing countries. In countries like Saudi Arabia it is critical to manage this resource and maximize the use. In the area of water treatment, such as ground water or industrial waste water treatment, there is an ever-increasing need to remove undesirable and even toxic contaminants, particularly heavy metal contaminants, from water. Many industrial processes utilize aqueous solutions of heavy metals, such as lead in the manufacture of batteries, and chromium or copper in electroplating solutions.
Prior art processes have utilized different types of adsorbents, such as activated carbon, activated sludge, various types of natural clays, carbon aerogels, coirpith carbon, natural zeolites and even date pits. Likewise, heavy metal removal can be accomplished through expensive ion exchange resins.
Prior art references have disclosed several adsorbents such as dithiocarbamate bond-containing low molecular weight compound, amorphous silica and activated carbon powder, granulated with a vinyl acetate polymer binder and clay as a thixotropic excipient (Tarao et al., U.S. Pat. No. 4,133,755), organically modified smectite clay, or organoclay to adsorb heavy metals (Cody et al., U.S. Pat. No. 5,667,694) and Oomura et al., (U.S. Pat. No. 5,256,615) discloses a granular inorganic ion exchanger which is obtained by heating at 400° C. or higher and obtaining a granular mixture from a metal alkoxide such as Si(OMe)4 or hydrolyzate thereof, a clay mineral such as sepiolite and an inorganic ion exchanger such as antimony pentoxide. Unfortunately, the removal of such heavy metals from the water used in these processes has proven to be not only difficult but also expensive.